As an individual ages, the eye is less able to accommodate, or bend the natural lens, to focus on objects that are relatively near to the observer. This condition is known as presbyopia. Similarly, for persons who have had their natural lens removed and an intraocular lens inserted as a replacement, the ability to accommodate is absent.
Among the methods used to correct for the eye's failure to accommodate are lenses that have more than one optical power. In particular, multifocal contact and intraocular lenses have been developed in which zones of distance and near, and in some cases intermediate, powers are provided.